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Hello anyone there?

The voltage levels for the NANDS appear good. Doesn't a bad NAND normally develop a short that would pull these down? pp0v9_nand0 0.9v pp1v2_nand0 1.2v pp2v5_nand0 2.5v ppvin_p3v8nand0 3.8v I noticed ppvdd_ldo_nand0_ocarina is only 1.4v rather than schematics 2.5v Before the CD3217 negotiate...

I understand you are saying 3V3_S2 comes from the U8100 and there may be problems with that chip and that chip has a healthy power supply in PP3V8_AON_VDDMAIN. But is it being told to turn on? In FlexBV notes there is a list of things that come before "step 11 (Many rails appear now)". Is that...

Yes 3V3_S2 is 3.3v on the good board

But the asymmetry described in my post #6 is not present on the working board. The rom gets 3.3v no matter which channel is powered. Anyway do you suggest I replace U8100?

Ive just taken delivery of a locked identical board that gets to 20v. Ive just taken its CD3217s and I still get that asymmetry described in my post #6. So the rom only gets 3.3volts when charger on channel0 and 0.5v when on channel1. There are no voltages on inductors around U8100.

PP3V3_S2_UPC 0.58v PP1V25_S2 0v PP3V8_AON_VDDMAIN 3.8v

OK the original CD3217 back in their places. ppbus_aon 12.3v 3v8_aon 3.8v When charger connected to channel 0 pp3v3_upc0_ldo [which powers the ROM] only gets 3.3 volt when pp3v3_upc1_ldo sits at 0.4v when charger connected to channel 1 pp3v3_upc0_ldo [which powers the ROM] gets 0.4 volts...

Pressing power button when on charger [or on battery] would result in Apple logo for 2 seconds before shutoff. Original battery was not charging. Battery replaced, battery now charges. Given a good charge. Still only reaches Apple logo before shutoff. Corrosion on CF800, CF813 but DM voltages...

Ah thought left hand side CD3217 were replaceable with purchasable ones. Good job I kept originals. Im going to put them back and post status again!

The point I am making is that ROM chip is only getting the correct voltage on one channel. Something seems wrong and Im wondering if this is what stopping it shift to 20v. Ive replaced both CD3217 with new and now Im wondering if I have overtemped one.

ppbus_aon 12.3v 3v8_aon 3.8v When charger connected to top USBC port [nearest screen] pp3v3_upc0_ldo [which powers the ROM] only gets 3.3 volt when pp3v3_upc1_ldo sits at 0.4v when charger connected to lower USBC port pp3v3_upc0_ldo [which powers the ROM] gets 0.4 volts pp3v3_upc1_ldo sits...

Tried DFU revive with trackpad, battery and touchid connected. Still seeing apple logo and progress bar. But I am getting another error message and didn't spot when it changed from 1. AMRestoreErrorDomain 1101 Failed to handle message type ASR invertor error I'm seeing heat of 70c on the...

No response as I try safe mode. No response as I try target mode. Wonder if restore might make it good but customer only interested in his data. = no profit on no fix no fee basis sadly.

Revive ended with "system cannot be restored on this device" code 1 I did get apple logo and time bar appear on screen. AC2 now showing Apple Controller square. So is the pp1v2_s3 0v controlled by the system and nothing can be done if a revive does not complete? Ive never seen any process under...

It comes up saying RECOVERY. Customer has valuable data

Fans 100% clogged Had very small amount of corrosion around R9581 but 2.5volts seen at all NAND. Corrosion removed and C9588, R9588, C9582, R9581. 2.5volt still there. ppbus_g3h 12.6v ppbus_hs_cpu 12.6v ppbus_hs_oth5v 12.6 ppvcc_s0_cpu 0v pp1v2_s3 0v pp3v3_g3h_rtc_x 3.3v all_sys_pwrgd 0v...

I tried replacing the SOC ROM from a donor and did see a different failure message. "Gave up waiting for device to transition from dfu state to dfu state." But I mostly get error 21. What does it mean when AC2 presents the image of an open Macbook ? I saw this a few times. Is this a good thing...

Im able to get the Macbook into DFU mode with the board back in the case. Unfortunately both revive and restore end up with unknown error 21. How to go from here?

No corrosion visible. Fan full speed when in case with all peripherals attached. ppbus_aon 12v pp3v8_aon 1.8v pp3v3_aon 3.3v pp5v_aon 5v pp1v8_aon 1.8v Presuming your advise might be to do a dfu restore I checked to see if I can get it into DFO mode.... With 2 microswitches wired to board to...